An atypical concentration or presence of substances in body fluids or in body lumens may be indicative of the biological condition of the body. For example, the presence of elevated concentrations of red blood cells in the gastrointestinal (GI) tract may indicate different pathologies, depending on the location of the bleeding along the GI tract. Likewise, abnormalities in the physical conditions of the body, such as elevated temperature, may indicate pathology. Early detection, identification and location of abnormal conditions may be critical for correctly diagnosing and treating various pathologies.
Medical detection kits are usually based on in vitro testing of body fluid samples for the presence of a suspected substance. A known in vitro test is, for example, an agglutination test. Agglutination tests typically rely on the ability of an antibody to form large cross-linked antibody-antigen complexes that precipitate out of a solution. The process of agglutination normally includes 2 steps: sensitization (involves the attachment of antibodies (Ab) to antigens (Ag)) and lattice formation (cross lining between sensitized particles, which results in visual agglutination). Some factors can enhance these reactions, for example, pH, temperature, incubation time, ionic strength (salt concentration) of the suspending solution and so on.
Agglutination reactions, also referred to as the indirect Coombs test, usually involve the precipitation of cells. Frequently, indirect cross-linking is used to form the aggregation. A secondary antibody may be added that binds to the primary antibodies that have bound to their epitope on the surface of the cell. Another known group of agglutination tests are the Latex Agglutination Tests (LAT). These immunoassay tests have been in clinical use for more than 50 years. The tests are used to detect the presence of an antibody or antigen in a variety of in vitro samples of bodily fluids including saliva, urine, cerebrospinal fluid, gastrointestinal secretions or blood. Depending on the sample under investigation, and the specific substance one is looking for, either antibodies or antigens are attached to latex beads (typically, spherical beads). When the corresponding antigen or antibody is present, the latex beads agglutinate, i.e. clump together into visible particles, when mixed or come to contact with the sample. The latex beads may be replaced by other polymers such as polystyrene or even gold particles.
Agglutination tests are typically performed on glass slides, “cards” with depressions for adding Ag and Ab or tubes and strips on which the agglutination exposes the underlying colored markers.
In vitro testing of samples does not easily enable the localization or identification of the origin of an abnormally occurring substance. In many instances localizing an abnormally occurring substance in a body lumen greatly contributes to the identification of pathology, and the proper type of treatment and thus contributes to the facile treatment of the identified pathology. For example, bleeding in the stomach may indicate an ulcer while bleeding in the small intestine may indicate the presence of a tumor. The detection of some conditions in the GI tract, such as bleeding, is possible by endoscope. However, this possibility is limited to the upper or lower GI tract. Thus, conditions in other parts of the GI tract, such as the small intestine, are not easily detected by endoscopy.
There is therefore a need for a system and method that may enable the localization or identification of the origin of an abnormally occurring substance throughout body lumens.